1. Field of the Invention
The present invention relates to a portable inhaler by means of which a user can inhale medicine.
2. Description of the Related Art
Inhalers designed to eject micro-droplets of medicine into an air flow being breathed in by a user by way of a mouthpiece (inhalation piece) on the basis of the principle of ink-jet systems so as to allow the user to inhale medicine have been developed (see Japanese Patent Applications Laid-Open No. 2004-290593 and No. 2004-283245). Such inhalers have an advantage that a predetermined dose of medicine can be accurately atomized as uniform droplets.
The ejection head for ejecting medicine to be inhaled by a user indispensably requires an element for generating ejection energy and electric power needs to be supplied to the ejection head. Generally, a medicine cartridge is formed by integrally combining an electrical connection section for supplying electric power from a power source arranged in an inhaler body and an ejection head. Such a medicine cartridge may be so formed as to be removably mountable in an inhaler body.
At least when ejecting medicine, an electric circuit needs to be established to supply electric power to the ejection head. However, in an electrically standby status where an electric circuit is established although the inhaler is not in use, medicine can be ejected at an unintended timing in an unexpected situation by an erroneous operation that can take place automatically or by human error.
A scheme for capping the needle of an electric injector when the electric injector is not in use so as to intercept the electrical connection of the injector in order to prevent medicine from being inadvertently ejected is known (see Japanese Patent Application Laid-Open No. H04-312469).
A mouthpiece as described in Japanese Patent Applications Laid-Open No. 2004-290593 or No. 2004-283245 can be so formed as to be removably mountable in an inhaler body. Since the user touches the mouthpiece with his or her mouth, the mouthpiece needs to be cleaned periodically and sanitarily controlled. A removably mountable mouthpiece can be serviced with ease from a sanitary point of view.
The amount of medicine ejected from an inhaler is equal to the dose of medicine to be administered to a user so that it is important to control the amount of medicine to be ejected from an inhaler if compared with an ink-jet recording apparatus particularly when the medicine is costly because the medicine should not be wasted by any means. Therefore, the ejection head of an inhaler is desirably electrically energized only when the inhaler ejects medicine. However, such an inhaler has not been provided to date. With the arrangement of using a cap to intercept the electrical connection when an injector is not in use as described in Japanese Patent Application Laid-Open No. H04-312469, the electrical connection is restored once the cap is taken off so that the injector can be inadvertently operated. In other words, the inhaler cannot break the electrical connection perfectly when the inhaler is not in use.